About 565,000 acres of irrigated land on the Eastern Snake River Plain could be dried up if a trout farm prevails in an upcoming water call case now before the Idaho Department of Water Resources.

For years, a water call filed by Rangen Inc., of Hagerman, Idaho, was dismissed as futile due to the tiny amount of water the company stood to receive, as calculated using the state’s Eastern Snake Plain Aquifer groundwater model, known by the acronym ESPAM 1.1.

But IDWR’s release last year of a new model — ESPAM 2.1 — has upped the ante in Rangen’s claims of injury and set into motion a high-stakes battle that could impact Idaho water law for years to come.

“This could affect probably more than half of the agricultural production on the Eastern Snake Plain,” said Lynn Tominaga, executive director of Idaho Ground Water Appropriators Inc., whose members would be most affected by Rangen’s water call.

The Rangen case is scheduled to be heard during the first two weeks of May, with IDWR Director Gary Spackman presiding as the hearing officer. Experts say it will set precedents regarding ESPAM 2.1. It will also weigh the concept under Idaho appropriation law of “first in time, first in right” against the need to optimize beneficial uses of the state’s water.

Rangen is seeking to curtail all pumpers with priority dates junior to 1962 drawing from the vast aquifer, which covers about 11,000 square miles of Southeast Idaho. The decision may still be appealed in district court, and the parties involved acknowledge a mitigation agreement would likely head off any curtailment.

“You have to shut down the entire ESPA to get very little water down to that spring,” Tominaga said of the case.

Because Rangen’s spring is fed through a long, man-made tunnel, the pumpers also contend the fish farm’s water should be treated as a groundwater right, requiring Rangen to try deepening its “well” before pursuing curtailment.

Rangen is primarily a fish feed manufacturer and uses its farm to test products that are under development. Idaho Power Co. buys Rangen’s trout for stocking lakes and rivers.

Rangen officials and their attorneys declined to comment for this story.

Declining flows

The Thousand Springs reach of the Snake River extends 30 miles south of Hagerman, where the 58-degree clean, oxygenated water flows from the canyon walls. The area’s hatcheries use it to produce more than three-quarters of the U.S. commercial trout supply.

Its flows, however, have been declining since the mid-1950s.

Average annual flows to Rangen’s spring were 58.7 cubic feet per second in 1972 and dropped below 15 cfs in 2012, according to IDWR.

Groundwater users, however, emphasize pumping is only one of many factors behind the decline. Since the 1960s, farmers have phased out flood irrigation in favor of more efficient sprinklers, reducing the amount of surplus water left to seep into the aquifer.

Also, in 1964, Palisades Dam was completed, and water that was previously allowed to run through canals throughout winter was stored, further reducing seepage into the aquifer. Prolonged droughts have also played a role, Tominaga said.

T.J. Budge, an attorney representing the groundwater pumpers, said though spring flows have decreased from their peak in the mid-1950s, they remain higher than historic levels.

“The amount of water stored in the aquifer increased dramatically during the first half of the 20th Century because of flood irrigation,” Budge said.

Longstanding issue

The controversy surrounding the aquifer has been around more than a decade.

In 2000, several spring users approached the state about the declining flows, starting a dialogue among the water users. Those discussions failed, and the Rangen, Clear Springs/Blue Lakes and Clear Lakes trout farms all issued delivery calls against groundwater users.

In Rangen’s case, the parties involved in the call agreed in 2004 to a mitigation plan, which was approved by IDWR Director Karl Dreher. A few months later, however, the department completed its new groundwater model, ESPAM 1.1. Based on that model, Dreher rescinded his approval of the plan in March of 2005, finding that curtailment of all of pumpers with a clear impact to Rangen’s spring would yield an insignificant amount of water.

Dreher also introduced a concept that’s been central to Idaho groundwater cases ever since. He established a 10 percent “trim line,” excluding from curtailment calls any pumping that would deplete Rangen’s flows by less than 10 percent of a junior water right holder’s total consumption. Dreher based the trim line on the margin of error in the model, also emphasizing the need to maximize use of water.

Rangen argues in its filings that the latest version of the model, ESPAM 2.1, is calibrated based on more data, increasing its accuracy, and can now provide estimates specific to individual springs, opening the door to reducing or eliminating the trim line and including all junior water right holders as far away as Rexburg.

With the 10 percent trim line, only junior water right holders in the immediately vicinity of the fish farm would be affected by the water call. Absent a trim line, the updated model estimates that curtailing all junior rights throughout the aquifer would increase Rangen’s flows by 18 cfs.

Trout farms bought

Around the time that Dreher found Rangen’s claims to be futile under ESPAM 1.1, the model nonetheless showed material injury to Blue Lakes and Clear Springs.

Dreher ordered curtailment of junior rights holders within the Magic Valley area north of the Snake River, using in a 10 percent trim line. Both parties appealed the case all the way to the Idaho Supreme Court. On March 17, 2011, the high court upheld the 10 percent trim line, rejecting the pumpers’ claims that economic losses would outweigh the benefits of curtailment but acknowledging the public interest of maximizing use of water.

To settle the case, groundwater users spent $30 million to purchase the Clear Lakes, Rim View and Blue Lakes trout farms. They transferred 120 cfs of Clear Lakes water to Clear Springs, which agreed to make no more calls against groundwater users.

“The real drawback to the solution we arrived at is it didn’t do anything to change the water balance in the aquifer itself,” said Randy MacMillan, Clear Springs vice president of research. “We still have to figure out how to stabilize and improve the condition of the aquifer, not just for Clear Springs, but for all users.”

Another area trout farm, Seapac of Idaho, leases Blue Lakes from the pumpers at a substantial discount to avert a potential call.

Tominaga said his organization will spend hundreds of thousands of dollars in legal and expert witness fees to litigate the remaining case with Rangen.

The other players

It’s more than 220 miles from the Fremont-Madison Irrigation District to Rangen’s fish farm. The district’s members often ask their attorney, Jerry Rigby, why they’re involved in a water call made so far away.

If IDWR rules not to use a trim line, five of Rigby’s groundwater wells, used to supplement surface water rights, could be curtailed, along with several members’ wells.

ESPAM 2.1 also increases the number of acres in Rigby’s district considered to be within the aquifer, subjecting them to Rangen’s call. Rigby said the wells in question “have made the difference for crops like potatoes maturing or not.”

He explained the district also intervened in the case to weigh in on the new model’s use.

“This has become a test case. It’s far bigger than Rangen,” Rigby said.

Rigby, a former Idaho Water Resource Board member, believes Idaho law requires priority dates to be honored in a way that doesn’t prohibit junior right holders from using water to its full economic potential. The principle precludes senior right holders from diverting more than needed, based on historic use, he said.

The City of Pocatello, which intervened in the case, has spent more than $200,000 to defend several wells from Rangen’s call, said city attorney Dean Tranmer. According to Pocatello’s calculations, it would take a decade for curtailment of the city’s junior wells to increase Rangen’s flows by 0.014 cfs.

“If we were to shut our wells down and it wouldn’t show up at Rangen’s diversion where they get their water in 20 years, is that reasonable? Is that really what the Appropriation Doctrine is all about — first in time, first in right and to heck with everybody else, no matter what?” Tranmer asked.

A coalition of surface water users, which includes seven Idaho irrigation districts, intervened in support of Rangen’s position on ESPAM 2.1. The coalition, represented by Twin Falls attorney Travis Thompson, is awaiting a Supreme Court ruling on its water call against groundwater pumpers, in which a 10 percent trim line has already been upheld.

“That’s our interest in this (Rangen) case is how the model is used and how the director treats it,” Thompson said. “The reports that have been filed by our experts have stated we think the modeled results are the best science available. They shouldn’t be qualified by any plus or minus or any margin of error.”

Water flows shrink

Ronald Hardy, director of the University of Idaho’s Aquaculture Research Institute, worked at the Rangen facility for much of 2004 and 2005, while the university leased space from the company to complete a renovation.

He estimates Rangen’s flows were double current levels back then.

“They were built in the first place to do farm-scale studies for their feed products. They do not have enough (water) to do that any more,” Hardy said.

Experts hired by the pumpers will claim Rangen’s facility, built in 1963, could raise more fish with its existing amount of water. Rangen has hired a former employee, fishery research biologist and consultant Charlie Smith, as an expert witness to testify on how lack of water has affected operations. Smith’s report includes photographs of Rangen’s dry fish raceways covered in weeds.

“The primary factor limiting the carrying capacity of the Rangen facility is the availability of water,” Smith concluded.

Optimizing use

U of I hydrology professor Gary Johnson teaches students Idaho’s appropriation policies seek a balance within the bounds of the law that’s “socially and economically acceptable.”

He considers a 10 percent trim line to be a reasonable approach tested repeatedly in court.

“If you cut off a huge amount of water and only one drop reaches Rangen Springs, that’s unreasonable,” Johnson said. “When you start getting down to about a hundredth of a percent, you’re starting to get into that unreasonable range.”

MacMillan, the Clear Springs researcher, believes the concept of putting water to an optimal use applies only to unappropriated water.

“Water should be given to the most senior water right holder first,” MacMillan said. “That’s what it says in the constitution.”